What do I have to do to get my husband to quit mentioning some old girlfriends name?

So my husband left me in October of 08' for a girl that he had been talking to. To make a long story short she stoped talking to him and he begged me to let him back. We have a little girl together and I genuinely care about him so I let him come back. This was in February 09'. He still constantly mentions her around me. For example: he says, "wanna ride convertable?" I say, "Not really it looks like rain and we've had it down all day." He then counters with. "Jane always wanted to ride convertable...." And it's not to hard to imagine where that conversation goes. Then to boot when I get upset he then turns it on me and says that I'm mean to him. So this brings me back to the question at hand how do I get him to stop mentioning her, or is it just to soon for him to have forgotten about her?